The following methods have been known as methods for producing a benzylamine derivative represented by the general formula (5) and a secondary amine derivative represented by the general formula (9) used as pharmaceutical intermediates.
For example, Patent Documents 1 and 2 disclose methods in which a benzylamine derivative represented by the general formula (5) is produced by using a compound prepared by selectively protecting only one primary amino group of readily-available 1,4-diaminobutane with a t-butoxycarbonyl (Boc) group as a starting material, and a secondary amine derivative represented by the general formula (9) is produced from the benzylamine derivative represented by the general formula (5).
An amine derivative disclosed in Patent Documents 1 and 2, which is effective against diseases such as HIV virus infection, rheumatism, or cancer metastasis, can be easily derived from the benzylamine derivative represented by the general formula (5) using the methods disclosed in Patent Documents 1 and 2.    [Patent Document 1] WO 2004/024697    [Patent Document 2] WO 2005/085209
However, since the methods disclosed in Patent Documents 1 and 2 require multiple introduction/deblocking of an expensive protecting group t-butoxycarbonyl (Boc) in order to protect the primary amino group, an increase in the number of steps, an increase in cost, a decrease in yield, and the like are caused. Moreover, these methods are not satisfactory for industrial production of the benzylamine derivative represented by the general formula (5) and the secondary amine derivative represented by the general formula (9) due to a step using highly volatile and poisonous dichloromethane as a solvent. Since these methods require plural purification steps using silica gel chromatography, these methods undergo a complicated operation, an increase in the number of steps, an increase in cost, a decrease in yield, and the like, thus these methods were not practical.
Various bactericides have been put to practical use based on the research and development of agricultural/horticultural disease protective agents over many years. These bactericides have contributed to labor saving and an increase in productivity. On the other hand, development of a compound useful as a bactericide which has reduced toxicity to humans and animals and increased handling safety has been desired.